Dissolution method

ABSTRACT

A method that can efficiently dissolve a water-soluble component contained in a gas with smaller energy consumption is provided. A mist is produced from a liquid. The mist and carrier air is mixed to produce mist-containing air. A solution gas and the mist-containing air are supplied to a static mixer. The solution gas and the mist-containing are mixed by using the static mixer. The liquid mist is brought in contact with the solution gas to dissolve a water-soluble component that is contained in the solution gas into the liquid mist. The liquid mist that contains the water-soluble component dissolved aggregates and produces a solution that contains the water-soluble component dissolved.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority under 35 U. S. C. § 119 to Japanese Patent Application No. 2019-135676 filed on Jul. 23, 2019, the contents of which are incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION 1. Technical Field

The present disclosure relates to a method of dissolving a water-soluble component that is included in a soluble gas into a liquid.

2. Description of Related Art

Methods that use a static mixer to mix a gas and a gas or a gas and a liquid have been developed (See Japanese Laid-Open Patent Publication Nos. JP H09-267,023 A (1997), JP H07-42,620 A (1995), and JP H10-281,012 A (1998).

JP H09-267,023 A (1997) discloses a deodorization apparatus of mixing ozone and gas that contains a malodorous substance by using a static mixer. JP H07-42,620 A (1995) and JP H10-281,012 A (1998) disclose apparatuses that use a static mixer to mix fuel and air to be supplied to a spark ignition internal-combustion engine.

The static mixer disclosed in JP H09-267,023 will efficiently mix the gas, which contains a malodorous substance, and the ozone whereby effectively deodorizing the malodorous substance by an effect of ozone. The static mixers disclosed in JP H07-42,620 and JP H10-281,012 will evenly mix the fuel and air. The static mixers will reduce temperature unevenness of exhaust-gas from the spark ignition internal-combustion engine by supplying evenly mixed fuel and air to the engine to improve combustion efficiency whereby fully treating the exhaust gas through a three-way catalytic converter. The static mixers disclosed in the above Publications evenly mix a gas and a gas or fuel and air without using power.

As disclosed in the above Publications, the static mixers efficiently mix two fluids without consuming power. In particular, in mixture of a liquid and a gas, in the case in which the liquid is brought into a fine mist of liquid and in contact with the gas, a total contactable area between the liquid and the gas can be larger. In this case, a water-soluble component that is contained in the gas can be efficiently dissolved in the liquid.

Such a fine liquid mist can be produced by oscillating a liquid at an ultrasonic frequency so that a fine liquid mist is separated from the liquid by using oscillation energy or by spraying a liquid by using a spray device and exposing the liquid sprayed to an electric field (electrostatic atomization). Ultrasonic oscillation and electrostatic atomization have a feature that can produce a very fine liquid mist. Because a fine liquid mist can have a very large contactable area with a gas, a water-soluble component that is contained in the gas can be efficiently dissolved in the liquid mist. However, such a fine liquid mist will be likely to evaporate. Such a gas that evaporates from the fine liquid mist cannot dissolve the water-soluble component contained in the gas. For this reason, even if a fine liquid mist is produced to have a large total contactable area with a gas that contains water-soluble component, the water-soluble component, which is contained in the gas, will not be efficiently dissolved in the liquid mist. Because the fine liquid mist produced cannot efficiently dissolve the water-soluble component, which is contained in the gas, energy consumption to dissolve the water-soluble component will be large.

Therefore, the present disclosure has been developed for solving the disadvantage. It is an important object of the present disclosure to provide a method of efficiently dissolving a water-soluble component that is contained in a gas with smaller energy consumption.

SUMMARY OF THE INVENTION

A method according to the present disclosure is a method of dissolving a water-soluble component of a soluble gas in a liquid. The method includes production of a fine mist of liquid, production of mist-containing air, supply of a soluble gas and the mist-containing air, mixing of the soluble gas and the mist-containing air, contact between the liquid mist and the soluble gas, and aggregation of the liquid mist. The fine mist is produced from a liquid 9 by ultrasonic oscillation or electrostatic atomization in the production of a fine mist of liquid. The mist and carrier air is mixed to produce the mist-containing air in the production of mist-containing air. The soluble gas and the mist-containing air are supplied to a static mixer 2 in the supply of a soluble gas and the mist-containing air. The soluble gas and the mist-containing are mixed by using the static mixer 2 in the mixing of the soluble gas and the mist-containing air. The liquid mist is brought in contact with the soluble gas to dissolve a water-soluble component that is contained in the soluble gas into the liquid mist in the contact between the liquid mist and the soluble gas. The liquid mist that contains the water-soluble component dissolved aggregates and produces a solution that contains the water-soluble component dissolved in the aggregation of the liquid mist.

The method can efficiently dissolve a water-soluble component that is contained in a gas with smaller energy consumption.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the present disclosure and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:

FIG. 1 is a block diagram showing a dissolution apparatus that can be used for a dissolution method according to an embodiment of the present disclosure;

FIG. 2 is a schematic diagram showing an atomizer in the dissolution apparatus shown in FIG. 1;

FIG. 3 is an enlarged cross-sectional view showing a connection structure of an ultrasonic oscillator;

FIG. 4 is a schematic perspective view showing an exemplary static mixer;

FIG. 5 is a block diagram showing a dissolution apparatus that can be used for a dissolution method according to another embodiment of the present disclosure; and

FIG. 6 is an enlarged cross-sectional view showing a structure of an atomization unit.

DETAILED DESCRIPTION

The following description will describe embodiments according to the present disclosure with reference to the drawings. In the following description, although terms for indicating particular directions or positions (e.g., “upper” and “lower”, and other terms including these terms) will be used as necessary for ease of understanding the present with reference to the drawings, the technical scope of the present disclosure is not limited by these terms. Portions attached with the same reference sign in different drawings show the portions or members same as or similar to each other.

It should be appreciated, however, that the embodiments described below are illustrations of a dissolution method to give a concrete form to technical ideas of the disclosure, and a dissolution method of the disclosure is not specifically limited to description below. Unless otherwise specified, any dimensions, materials, shapes and relative arrangements of the parts described below are given as an example and not as a limitation. In addition, the description for one embodiment can be applied to other embodiments or examples. Additionally, the sizes and the arrangement relations of the members in the drawings are occasionally exaggerated for ease of explanation.

In this specification, a “static mixer” refers to a mixer that mixes two or more fluids not by consuming power by itself but by using inertia forces of the fluids.

A method according to a first aspect of the present disclosure is a method of dissolving a water-soluble component of a soluble gas in a liquid. The method includes ultrasonic oscillation of a liquid, forcedly blowing of air, supply of a soluble gas and mist-containing air, mixing of the soluble gas and the mist-containing air, contact between the liquid mist and the soluble gas, and aggregation of the liquid mist. The liquid is oscillated at an ultrasonic frequency to produce a liquid column in the ultrasonic oscillation of a liquid. Air is forcedly blown to the liquid column produced to separate a mist of the liquid from the liquid column whereby producing mist-containing air in the forcedly blowing of air. The soluble gas and the mist-containing air are supplied to a static mixer in the supply of a soluble gas and mist-containing air. The soluble gas and the mist-containing are mixed by using the static mixer in the mixing of the soluble gas and the mist-containing air. The liquid mist is brought in contact with the soluble gas to dissolve a water-soluble component that is contained in the soluble gas into the liquid mist in the contact between the liquid mist and the soluble gas. The liquid mist that contains the water-soluble component dissolved aggregates and produces a solution that contains the water-soluble component dissolved in the aggregation of the liquid mist.

In particular, the dissolution method includes supplying a soluble gas that contains a water-soluble component and a liquid mist that is produced by ultrasonic oscillation to a static mixer, bringing the liquid mist, which has a large surface area, in contact with the soluble gas in the static mixer to dissolve a water-soluble component of the soluble gas into the liquid mist, and aggregating the liquid mist that contains the water-soluble component dissolved to produce a solution. In the dissolution method, the liquid mist and the water-soluble component of the gas are mixed in the static mixer, so that the water-soluble gaseous component is dissolved in the liquid mist. In the conditions in the static mixer, because a gaseous water-soluble component will be mixed with fine droplets of the liquid mist, the total contactable area between the liquid mist and the gaseous water-soluble component can be very large. As a result, the water-soluble component can be quickly dissolved in the liquid. When the liquid is brought in contact with the water-soluble component, the mist is required to be held in a liquid state until contact with the water-soluble component. If the mist evaporates, the water-soluble component will not be dissolved in the liquid even when the water-soluble component and the mist evaporating are efficiently mixed. The static mixer mixes the liquid mist as droplets and the water-soluble component to efficiently dissolve the water-soluble component in the liquid. The water-soluble component is efficiently dissolved in the liquid. After that, the liquid mist that contains the water-soluble component dissolved aggregates and produces a solution that contains the water-soluble component dissolved. Because a very large contactable area between the liquid mist and the water-soluble component can be provided in this method, the water-soluble component can be quickly dissolved in the liquid mist. In addition, the liquid mist aggregates and produces a solution that contains the water-soluble component dissolved. As a result, the water-soluble component can be very efficiently dissolved in the liquid. Consequently, in the case in which the water-soluble component is a malodorous gas, the malodorous gas can be efficiently dissolved in the liquid for deodorization.

A method according to a second aspect of the present disclosure is a method of dissolving a water-soluble component of a soluble gas in a liquid. The method includes spraying of a liquid, electrostatic atomization, mixing of a fine mist and carrier air, supply of a soluble gas and mist-containing air, mixing of the soluble gas and the mist-containing air, contact between the liquid mist and the soluble gas, and aggregation of the liquid mist. The liquid is sprayed by using a spray device in the spraying of a liquid. A sprayed mist of the liquid is exposed to an electric field to produce the fine mist in the electrostatic atomization. The fine mist and the carrier air are mixed to produce mist-containing air in the mixing of a fine mist and carrier air. The soluble gas and the mist-containing air are supplied to a static mixer in the supply of a soluble gas and the mist-containing air. The soluble gas and the mist-containing are mixed by using the static mixer in the mixing of the soluble gas and the mist-containing air. The liquid mist is brought in contact with the soluble gas to dissolve a water-soluble component that is contained in the soluble gas into the liquid mist in the contact between the liquid mist and the soluble gas. The liquid mist that contains the water-soluble component dissolved aggregates and produces a solution that contains the water-soluble component dissolved in the aggregation of the liquid mist.

In particular, the dissolution method includes supplying a soluble gas that contains a water-soluble component and a liquid mist that is produced by in the electrostatic atomization to a static mixer, bringing the liquid mist, which has a large surface area, in contact with the soluble gas in the static mixer to dissolve a water-soluble component of the soluble gas into the liquid mist, and aggregating the liquid mist that contains the water-soluble component dissolved to produce a solution. In the dissolution method, the liquid mist and the water-soluble component of the gas are mixed in the static mixer, so that the water-soluble gaseous component is dissolved in the liquid mist. In the conditions in the static mixer, because a gaseous water-soluble component will be mixed with fine droplets of the liquid mist, the total contactable area between the liquid mist and the gaseous water-soluble component can be very large. As a result, the water-soluble component can be quickly dissolved in the liquid. When the liquid is brought in contact with the water-soluble component, the mist is required to be held in a liquid state until contact with the water-soluble component. If the mist evaporates, the water-soluble component will not be dissolved in the liquid even when the water-soluble component and the mist evaporating are efficiently mixed. The static mixer mixes the liquid mist as droplets and the water-soluble component to efficiently dissolve the water-soluble component in the liquid. The water-soluble component is efficiently dissolved in the liquid. After that, the liquid mist that contains the water-soluble component dissolved aggregates and produces a solution that contains the water-soluble component dissolved. Because a very large contactable area between the liquid mist and the water-soluble component can be provided in this method, the water-soluble component can be quickly dissolved in the liquid mist. In addition, the liquid mist aggregates and produces a solution that contains the water-soluble component dissolved. As a result, the water-soluble component can be very efficiently dissolved in the liquid. Consequently, in the case in which the water-soluble component is a malodorous gas, the malodorous gas can be efficiently dissolved in the liquid for deodorization.

In a dissolution method according to a third aspect of the present disclosure, a flow rate of air for producing the mist-containing air can be adjusted to keep the liquid mist in droplets in the static mixer.

In this method, a mist in the static mixer can be held in a liquid state by adjusting a flow rate of the air for mist-containing air. A relative humidity inside a static mixers can be reduced by reducing a flow rate of air for producing the mist-containing air. An amount of liquid mist evaporating can be minimized in the static mixer that has a lower relative humidity. As a result, a concentration of the liquid mist can be high. In the case in which a high concentration of liquid mist is mixed with a water-soluble component, a total contactable area between the liquid mist and the water-soluble component can be larger. Consequently, the water-soluble component can be efficiently dissolved in the liquid mist. In particular, the static mixer can keep a relative humidity inside the static mixer greater than 100% (supersaturation state). As a result, evaporation of the liquid mist can be reliably minimized so that a concentration of the liquid mist can be particularly high. Consequently, the water-soluble component can be more efficiently dissolved in the liquid mist.

In a dissolution method according to a fourth aspect of the present disclosure, a temperature or humidity inside the static mixer can be detected, and a flow rate of air that is forcedly blown to the liquid column is adjusted n accordance with the temperature or humidity detected.

A temperature rise inside a static mixer will reduce a relative humidity inside the static mixer. Such a relative humidity drop inside the static mixer will increase an amount of liquid mist evaporating. For this reason, a flow rate of air that is forcedly blown to the static mixer is adjusted in accordance with a temperature or humidity that are detected inside the static mixer to reduce a relative humidity drop inside the static mixer to keep a high concentration of the liquid mist. As a result, the liquid mist, which has a large surface area, can be brought in contact with the water-soluble component. Consequently, the water-soluble component can be efficiently dissolved in the liquid mist. Air that is forcedly blown to a liquid column flows into the static mixer. If a flow rate of air that is forcedly blown into the static mixer forcedly is reduced, a flow rate of air that is forcedly blown to a liquid column is correspondingly reduced, and atomization efficiency decreases. The reason is that a mist cannot be efficiently separated from a surface of the liquid column by air blown to the liquid column. The dissolution method that detects a temperature or humidity inside the static mixer and adjusts a flow rate of air forcedly blown can control a flow rate of air blown to keep a relative humidity inside the static mixer greater than a predetermined value. Because the dissolution method that detects a temperature or humidity inside the static mixer and adjusts a flow rate of air forcedly blown can adjust an amount of air that is blown into the static mixer in consideration of both a concentration drop of liquid mist and production efficiency of a mist separated from the liquid column, atomization efficiency of the mist can be kept higher than a predetermined value without reducing a total contactable area between the liquid mist and the water-soluble component.

In a dissolution method according to a fifth aspect of the present disclosure, the soluble gas can contain air, and a flow rate of the soluble gas, which contains air, to the static mixer can be adjusted to keep the liquid mist in droplets in the static mixer.

A relative humidity inside a static mixer will vary depending on an amount of a soluble gas supplied. If an amount of a soluble gas supplied is increased, a relative humidity inside the static mixer is correspondingly reduced. As a result, a liquid mist is likely to evaporate. The reason is that an increase in an amount of the soluble gas supplied increases an amount of a gas component that is suppled as the soluble gas with respect to an amount of a liquid component as the mist collected into the static mixer. The method that controls a flow rate of the soluble gas supplied to the static mixer can minimize a flow rate of the soluble gas supplied to keep a relative humidity inside the static mixer higher than a predetermined value. As a result, a high concentration of liquid mist, which has a large surface area, can be brought in contact with the water-soluble component. Consequently, the water-soluble component can be efficiently dissolved in the liquid mist.

In a dissolution method according to a sixth aspect of the present disclosure, a temperature inside the static mixer can be detected, and the flow rate of the soluble gas, which contains air, to be supplied to the static mixer can be adjusted in accordance with the temperature detected.

In a dissolution method according to a seventh aspect of the present disclosure, a temperature inside the static mixer can be adjusted to keep the liquid mist in droplets in the static mixer.

In a dissolution method according to an eighth aspect of the present disclosure, an amount of the liquid mist to be supplied to the static mixer can be adjusted to keep the liquid mist in droplets in the static mixer.

In a dissolution method according to a ninth aspect of the present disclosure, a temperature inside the static mixer can be detected, and the amount of the liquid mist to be supplied to the static mixer can be adjusted in accordance with the temperature detected.

In a dissolution method according to a tenth aspect of the present disclosure, a temperature of the soluble gas to be supplied to the static mixer can be adjusted to keep the liquid mist in droplets in the static mixer.

In a dissolution method according to an eleventh aspect of the present disclosure, air can be supplied to the soluble gas, and an amount of the air to be supplied to the soluble gas can be adjusted. In addition, the temperature of the soluble gas to be supplied to the static mixer can be adjusted by the air-supply-amount adjustment.

In a dissolution method according to a twelfth aspect of the present disclosure, the water-soluble component of the soluble gas can be at least one selected from the group consisting of a malodorous component, ammonia, alcohol, volatile organic compound (VOC), soot, NOX, and SOX.

In a dissolution method according to a thirteenth aspect of the present disclosure, the liquid in which the water-soluble component of the soluble gas is dissolved can be water, alkaline water, or acid water.

First Embodiment

FIG. 1 is a block diagram showing a dissolution apparatus 100, which uses a method of dissolving a water-soluble component that is included in a soluble-component-containing gas (soluble gas) into a liquid. The illustrated dissolution apparatus 100 includes an atomizer 1, which oscillates a liquid 9 at an ultrasonic frequency to produce a fine mist of the liquid (atomization), a static mixer 2, which mixes mist-containing air that is supplied from the atomizer 1 and the soluble gas, and a collector 3, which is connected to the static mixer 2. The mist aggregates and is collected in the collector 3.

The apparatus shown in FIG. 1 can be used for a dissolution method that dissolves into a liquid a water-soluble component (e.g., malodorous component, ammonia, alcohol, volatile organic compounds (VOC), etc.) included in the soluble gas, and collects or remove the water-soluble component. The liquid 9 that dissolves the water-soluble component is a suitable liquid for dissolution of the water-soluble component. For example, water is used as the liquid 9 in a method of dissolving a malodorous component for deodorization. Alkaline or acid water is used as the liquid 9 in a method of collecting ammonia, alcohol, or volatile organic compounds. Specifically, acid water such as a hydrochloric acid aqueous solution is used to dissolve and collect ammonia included in a soluble gas. When a gas that contains ammonia contacts a hydrochloric acid aqueous solution, the ammonia becomes an ammonium ion and makes a union between the ammonium ion and a chloride ion in a hydrochloric acid to form an ammonium chloride, which will be dissolved in water. In order to efficiently dissolve and collect the water-soluble components, a liquid that can quickly dissolve the water-soluble component is selected as the liquid 9, which dissolves the water-soluble component included in the soluble gas.

The dissolution apparatus 100 shown in FIG. 1 supplies the fine mist to the static mixer 2, and collects the mist that contains the water-soluble component dissolved inside the static mixer 2 by using the collector 3. Droplets of the fine mist have a large surface area relative to their volumes. In other words, a large total contactable area between the mist and the soluble gas can be provided by the dissolution apparatus. The dissolution apparatus 100 shown in FIG. 1 produces in the atomizer 1 the mist from the liquid 9, and collects the mist that dissolves the water-soluble component after the mist aggregates in a cyclone 3A. The atomizer 1 includes an atomization chamber 10, an ultrasonic oscillator 11, a high-frequency power source 12, and a blower 20. The atomization chamber 10 accumulates the liquid 9 from which the mist is produced. The ultrasonic oscillator 11 can oscillate the liquid 9 at an ultrasonic frequency to protrude a liquid column P from a liquid surface level W whereby producing the mist. The high-frequency power source 12 is connected to the ultrasonic oscillator 11, and supplies high-frequency power to the ultrasonic oscillator 11 to oscillate at an ultrasonic frequency. The blower 20 blows air as a carrier gas toward the atomization chamber 10.

The atomization chamber 10 is a closed chamber for accumulating the liquid 9 the surface of which is kept at a predetermined liquid surface level W. The mist is produced from the liquid 9 in the atomization chamber 10. The mist produced is mixed with the carrier gas, and discharged as the mist-containing air from the atomization chamber 10. The atomization chamber can be not fully closed but can be partially opened. The atomization chamber 10 shown in FIG. 2 includes a feeding port 13, which is arranged lower than the liquid surface level. The liquid 9 can be supplied through the feeding port 13. An overflow port 14 is arranged to keep the liquid surface level of the liquid 9 at the fixed level. The liquid 9 is fed from the feeding port 13, and is discharged from the overflow port 14. Although the liquid surface level of the liquid 9 has been illustratively described to be kept at the fixed level by the overflow port 14 in the atomization chamber 10, the liquid surface level can be kept at the fixed level by adjusting a liquid amount that is supplied from the feeding port 13. In the case in which the liquid surface level is kept at a fixed level in the atomization chamber 10, a depth of the liquid that is oscillated at an ultrasonic frequency by the ultrasonic oscillator 11 can be kept at an optimal depth, which optimizes efficiency of atomization.

The liquid 9 is fed by a feed mechanism 15 to the atomization chamber 10. The feed mechanism 15 shown in FIG. 2 includes a liquid tank 16 for storage of the liquid 9 to be fed to the atomization chamber 10, and a liquid pump 17, which pumps the liquid 9 in the liquid tank 16 to the atomization chamber 10. The liquid pump 17 has an inlet side connected to the liquid tank 16, and an outlet side connected to the atomization chamber 10. The feed mechanism 15 can continuously feed the liquid 9 to the atomization chamber 10 from the liquid tank 16 by using the liquid pump 17.

The ultrasonic oscillator 11 is fastened on a bottom plate 18 of the atomization chamber 10 to water-tightly close an opening 18A of the bottom plate 18 as shown in an enlarged cross-sectional view of FIG. 3. The ultrasonic oscillator 11 has an electrode on its lower surface that is connected to the high-frequency power source 12. Electric power is supplied from the high-frequency power source 12 through the electrode to oscillate the ultrasonic oscillator 11 at an ultrasonic frequency. The high-frequency power source 12 is connected to the ultrasonic oscillator 11 through lead wire lines 19, and supplies high frequency power to the ultrasonic oscillator 11.

The blower 20 blows air as a carrier gas that carries the mist toward the liquid column P, which is produced by ultrasonic oscillation, as shown in FIG. 2. Air is blown toward a surface of the liquid column P to scatter the mist around the surface of the liquid column in the air whereby producing the mist-containing air. The blower 20 is controlled by the controller 4 and adjusts an amount of air that is supplied to the atomization chamber 10.

The ultrasonic oscillator 11 is horizontally arranged in the atomizer 1 as discussed above to vertically protrude the liquid column P from the liquid surface level W. The ultrasonic oscillator 11 can be inclined in the atomizer 1 to protrude the liquid column P in a slant direction from the liquid surface level W. Although the illustrated atomizer 1 has been illustratively described to include one ultrasonic oscillator 11, the atomizer 1 can have two or more ultrasonic oscillators. In this case, an amount of mist produced will be correspondingly increased. Also, an amount of mist produced can be adjusted by adjusting power supplied to the ultrasonic oscillator 11.

The atomizer 1 shown in FIG. 1 includes air and liquid heaters 21 and 22, which heats air and liquid 9, respectively. In the case in which the atomizer 1 heats air and the liquid 9, atomization efficiency can be high. As a result, an amount of the mist produced in unit time can be increased. The air and liquid heaters 21 and 22 are controlled by the controller 4, and adjust air and liquid temperatures, respectively.

The static mixer 2 efficiently mixes the mist-containing air supplied and the soluble gas so that the water-soluble component of the soluble gas can be dissolved in droplets of the liquid mist. The dissolution apparatus 100 shown in FIG. 1 includes a supply fan 5, which supplies the soluble gas to the static mixer 2, and an outside-air fan 6, which supplies outside air. The supply fan 5 is controlled by the controller 4 and adjusts an amount of the soluble gas to be supplied. The outside-air fan 6 is controlled by the controller 4 and adjusts an amount of outside air to be supplied. The dissolution apparatus 100 shown in FIG. 1 further includes a cooler 7, which cools the soluble gas. The soluble gas is cooled by the cooler 7 and then supplied to the static mixer 2. The cooler 7 is also controlled by the controller 4 and adjusts a temperature of the soluble gas after cooled.

Evaporation of the mist can be minimized in the static mixer 2 by the soluble gas that has a lower temperature and is supplied to the static mixer 2. The reason is that a high-temperature soluble gas brings the static mixer 2 to a high temperature and reduces a relative humidity inside the static mixer 2, and as a result the mist becomes likely to evaporate. A temperature of the soluble gas can be lowered by outside air that has a temperature lower than the soluble gas and is supplied from the outside-air fan 6. Also, the soluble gas can be cooled by the cooler 7. Accordingly, a temperature of the soluble gas can be brought to a lower temperature when the soluble gas reaches the static mixer 2.

The static mixer 2 mixes the soluble gas and the mist-containing air that flow through the static mixer 2. The static mixer 2 includes a tube member 25 and elements 26, which are arranged in the tube member 25 and form a plurality of in-line stages, as shown in a schematic perspective view of FIG. 4. The elements 26, which are arranged in a plurality of stages, of the static mixer 2 can change a flowing direction of the soluble gas and the mist-containing air between rightward and leftward, and between upward and downward in the tube member 25. Each element 26 is formed from a rectangular plate, which has a width corresponding to an inner diameter of the tube member 25 and a length preferably 1.5 times of the width, by twisting the rectangular plate 180 degrees. Clockwise-twisted elements 26A are formed by twisting the rectangular plate 180 degrees clockwise. Counterclockwise-twisted elements 26B are formed by twisting the rectangular plate 180 degrees counterclockwise. Clockwise-twisted elements 26A and counterclockwise-twisted elements 26B are alternately aligned in a main flow direction. The clockwise-twisted and counterclockwise-twisted elements 26A and 26B are orientated perpendicular to each other in the tube member 25 so that their edges perpendicularly intersect each other at boundaries between them. A flow of the soluble gas and the mist-containing air is divided into two flows at an edge of a first element of the elements 26. After that, each flow is repeatedly divided into two flows at an edge of a next element (downstream-side element) of the elements 26. As a result, a clockwise flow is changed to a counterclockwise flow and vice versa at each boundary in the static mixer 2. In the case in which a number of stages, which are formed by the clockwise-twisted and counterclockwise-twisted elements 26A and 26B alternately aligned in the static mixer 2, is large, the soluble gas and the mist-containing air can be more evenly mixed. Each flow is divided into two flows at an edge of each element 26 in the static mixer 2. For example, in the case in which 20 stages are formed by the clockwise-twisted and counterclockwise-twisted elements 26A and 26B in the static mixer 2, a division number is 2²⁰ (1,048,576). In this case, the soluble gas and the mist-containing air can be efficiently mixed, and the soluble gas and the mist will be efficiently moved relative to each other. Consequently, the water-soluble component of the soluble gas can be efficiently dissolved in the liquid mist. The length of the clockwise-twisted or counterclockwise-twisted elements 26A or 26B is relatively short (1.5 times its width). The static mixer 2 that has a number of stages formed by the relatively short elements 26 can efficiently dissolve the water-soluble component of the soluble gas in the liquid mist while keep its total length relatively short. On the other hand, a longer element 26 will enhance dissolution efficiency of the water-soluble component in the liquid mist.

The mist in a liquid state can dissolve the water-soluble component of the soluble gas. If the mist evaporates, the mist that has evaporated and is not liquid cannot dissolve the water-soluble component. In order to efficiently dissolve the water-soluble component of the soluble gas in the liquid, the static mixer 2 is required to flow the mist while minimizing evaporation of the mist. Evaporation of the mist can be reduced by supersaturation inside the static mixer 2, in other words, by bringing an interior of the static mixer 2 to a temperature lower than a dew-point temperature of the liquid. In order to minimize evaporation of the mist in the static mixer 2, the static mixer 2 includes a temperature sensor 27, which detects a temperature inside the static mixer 2, and a humidity sensor 28, which detects humidity inside the static mixer 2.

The controller 4 adjusts an environment in the static mixer 2 in accordance with signals that are provided from the temperature sensor 27 and the humidity sensor 28 to conditions that can minimize evaporation of the mist. The controller 4 shown in FIG. 1 adjusts temperatures and flow rates of the mist-containing air and the soluble gas so as to minimize evaporation of the mist in the static mixer 2. Also, the controller 4 adjusts a flow rate and a temperature of air as the carrier gas to be supplied to the atomizer 1, and a temperature of the liquid that is subjected to ultrasonic oscillation so as to control temperatures and humidities of the mist-containing air to be supplied to the static mixer 2. The reason is that a high-temperature soluble gas and a high flow rate of the air reduce a relative humidity inside the static mixer 2, and as a result the mist becomes likely to evaporate. For this reason, the controller 4 controls the air heater 21 and the liquid heater 22 in accordance with a temperature and a humidity that are detected inside the static mixer 2, and adjusts a flow rate of air to be supplied to the atomizer 1 in accordance with the temperature and humidity detected so that a relative humidity inside the static mixer 2 falls within a predetermined range. The controller 4 adjusts a flow rate of outside air to be supplied to the soluble gas in addition to a flow rate of the soluble gas so that a relative humidity inside the static mixer 2 falls within the predetermined range, which preferably corresponds to supersaturation in which the relative humidity is not lower than 100%, in other words, a temperature inside the static mixer 2 is not higher than a dew-point temperature. As a result, evaporation of the mist can be effectively minimized.

Atomization efficiency of the atomizer 1 can be high if a flow rate of air blown toward the liquid column P and a temperature of the air are high. Also, the atomization efficiency can be high if the liquid 9 is heated to a high temperature. The controller 4 adjusts a flow rate and a temperature of air to be supplied to the liquid column P in consideration of the atomization efficiency. If the flow rate and the temperature of the air are high, the atomization efficiency can be high but an evaporation rate of the mist in the static mixer 2 will increase. For this reason, the controller 4 adjusts the flow rate and the temperature of air to be supplied by the atomizer 1 to the liquid column P in accordance with a temperature and a humidity that are detected in the static mixer 2. The controller 4 preferably adjusts the flow rate and the temperature of the air to high values to increase the atomization efficiency while keeping the air inside the static mixer 2 supersaturated or almost supersaturated with moisture to minimize evaporation of the mist. The atomizer 1 that includes the liquid heater 22 adjusts the liquid to be heated to a high temperature within a range that keeps the air inside the static mixer 2 supersaturated or almost supersaturated with moisture.

An evaporation amount of the mist in the static mixer 2 varies depending on a flow rate and a temperature of the soluble gas to be supplied to the static mixer 2. If the soluble gas of a high temperature gas containing steam, and is cooled to a temperature lower than a dew-point temperature before supplied to the static mixer 2, evaporation of the mist in the static mixer 2 is not enhanced when the soluble gas is supplied. If the soluble gas has that a temperature higher than a dew-point temperature and a low relative humidity is supplied to the static mixer 2, a relative humidity inside the static mixer 2 decreases, and as a result evaporation of the mist is enhanced. In particular, if a large amount of the soluble gas that has a low humidity is supplied to the static mixer 2, a relative humidity inside the static mixer 2 will drop. To address such a relative humidity drop in which evaporation of the mist is enhanced, the soluble gas is cooled to increase a relative humidity inside the static mixer 2, or a relative humidity of the mist-containing air supplied from the atomizer 1 is reduced to keep a relative humidity inside the static mixer 2 higher than a predetermined value.

The soluble gas that has a high temperature can be cooled by a heat exchanger (not shown), and then by supplying low-temperature outside air that has a temperature lower than the soluble gas before supplied to the static mixer 2 as shown in FIG. 1. The heat exchanger cools the soluble gas preferably to a temperature lower than a dew-point temperature before the soluble gas is supplied to the static mixer 2. In the case in which the soluble gas is cooled by mixing the soluble gas and outside air, a relative humidity of outside air is preferably high. Such high humidity outside air can cool the soluble gas while keeping a relative humidity inside the static mixer 2 high.

The mist that dissolves the water-soluble component of the soluble gas aggregates and is collected in the collector 3. The cyclone 3A is arranged as the collector 3 shown in FIG. 1. The mist that dissolves the water-soluble component flows in a tangential direction of a cylindrical interior surface of the cyclone 3A so that the mist rotates along the interior surface and is attached onto the interior surface of the cyclone 3A by a centrifugal force. The mist attached aggregates and is discharged from the bottom of the cyclone 3A. Gas components of the soluble gas and the mist-containing air are discharged to the outside from a discharge tube 31 that is arranged in a central part of the cyclone 3A.

In the aforementioned dissolution apparatus 100, the soluble gas and the mist-containing air are supplied to the static mixer 2 so that the water-soluble component of the soluble gas is dissolved in the liquid mist in the static mixer 2, and the mist that dissolves the water-soluble component aggregates and is collected in the cyclone 3A of the collector 3. Finally, a solution that contains the water-soluble component dissolved can be produced. The liquid is oscillated at an ultrasonic frequency to produce a liquid column P, which protrudes from the surface level, in the atomizer 1, and air is forcedly blown by the blower 20 to the liquid column P to separate a mist of the liquid from the liquid column P whereby producing mist-containing air. The soluble gas and the mist-containing air are supplied to the static mixer 2 so that the soluble gas and the mist-containing are mixed. The liquid mist is brought in contact with the soluble gas to dissolve the water-soluble component that is contained in the soluble gas into the liquid mist. The liquid mist that contains the water-soluble component dissolved aggregates and produces a solution that contains the water-soluble component dissolved in the cyclone 3A of the collector 3. The controller 4 adjusts a flow rate and a temperature of the carrier gas that is blown into the atomizer 1, a temperature of the liquid that can be heated, and a flow rate and a temperature of the soluble gas in accordance with a temperature and a humidity that are detected in the static mixer 2 so as to keep the interior of the static mixer 2 to a temperature preferably lower than a dew-point temperature while efficiently producing the mist from the liquid. The mist and the soluble gas are brought in contact with each other in the static mixer 2 so that the water-soluble component is dissolved in the mist. The cyclone 3A collects the mist that contains the water-soluble component dissolved.

Second Embodiment

Although the aforementioned dissolution apparatus has been described to oscillate a liquid at an ultrasonic frequency to produce a fine mist of the liquid, a fine mist can be produced by spraying a liquid from a spray device and by exposing the liquid sprayed to an electric field. A dissolution apparatus 200 shown in FIG. 5 includes an electrostatic atomizer 40, which sprays a liquid 9 to produce a mist from a spray device 41. The spray device 41 is arranged in an upper part of a closed spray case 47 of the electrostatic atomizer 40, and sprays the liquid is from the upper side to the lower side. The electrostatic atomizer 40 further includes atomization electrodes 42, which are arranged in the spray case 47 and can produce a fine mist by applying an electrostatic effect on the mist that is sprayed from the spray device 41.

The spray device 41 includes a plurality of atomization units 50, which are arranged in the spray case 47 of the electrostatic atomizer 40 as shown in FIG. 5. One of the atomization units 50 is shown in FIG. 6. A plurality of capillary tubes 53 are arranged parallel to each other and fastened to a nozzle block 54 in the illustrated atomization unit 50. Each capillary tube 53 is formed of a metal narrow tube having an inner diameter 0.1 to 0.2 mm. The liquid is pressurized is suppled to each capillary tube. The liquid is then sprayed from an end of the tube so that a mist of the liquid is produced.

The nozzle block 54 includes a flange 54 a on its outer peripheral part. The capillary tubes 53 are arranged in a central part of the nozzle block 54. The nozzle block 54 shown in FIG. 6 includes a main part 54A, which includes the flange 54 a, and a plate part 54B, which is fastened to the main part 54A by screws. The capillary tubes 53 are fastened to the plate part 54B. The plate part 54B has through holes 54 x, which receive the capillary tubes 53. Each through hole 54 x has an interior shape corresponding to an exterior shape of the capillary tube 53 so that the capillary tube 53 is held in the plate part 54B almost without gap. A packing 55 is arranged on an interior surface of the plate part 54B to prevent liquid leakage through the through holes 54 x along the capillary tubes 53. The packing 55 is formed of an elastic material such as rubber, and airtightly closes a clearance between the capillary tube 53 and the plate part 54B. A sandwiching plate 56 is arranged to press the packing 55 to the plate part 54B. The packing 55 is sandwiched and deformed between the plate part 54B and the sandwiching plate 56 when fastened to the main part 54A. The sandwiching plate 56 also has through holes 56 x. The sandwiching plate 56 is arranged in a stepped section 54 b of the main part 54A. The packing 55 is pressed and elastically deformed between the main part 54A and the plate part 54B, which is fastened to the main part 54A when fastened to the main part 54A. The main part 54A includes a cylindrical part 54 c, which protrudes from a back surface of the main part 54A. The cylindrical part 54 c has an interior shape that can accommodate the capillary tubes 53, and an exterior shape on which external threads 54 d are formed. The capillary tubes 53 are accommodated in the cylindrical part 54 c of the main part 54A. A liquid-feeding socket 57, which feeds the liquid, is coupled to an end section of the cylindrical part 54 c.

The through holes 54 x are arranged in a plurality of ring-shaped lines on the plate part 54B of the nozzle block 54 shown in FIG. 6. Each capillary tube 53 protrudes from the nozzle block 54. The protruding part of each capillary tube 53 serves an electrical discharge protrusion 51. Each capillary tube 53 has a through center hole, which serves a fine spraying nozzle 52. The number of the capillary tubes 53, which are fastened to the nozzle block 54, corresponds to the number of the fine spraying nozzles 52 of the atomization unit 50. Each atomization unit 50 preferably has ten or more fine spraying nozzles, more preferably 20 or more, or most preferably 30 or more fine spraying nozzles 52. In this case, an amount of mist sprayed by one atomization unit 50 per unit time can be large. If the atomization unit 50 has too many of the fine spraying nozzles 52, its entire size becomes too large. In this embodiment, the atomization unit 50 has not greater than 100 fine spraying nozzles 52. A protruding amount of the capillary tube 53 that is arranged in the central part of the nozzle block 54 is greater than the capillary tubes 53 that are arranged on the outer peripheral part of the nozzle block 54 so that ends of all the capillary tubes 53 entirely form a convex shape in the atomization unit 50 shown in FIG. 6. It is noted that protruding amounts of the capillary tubes 53 can be the same as each other. In this case, ends of all the capillary tubes 53 entirely form a flat shape.

The aforementioned atomization unit 50 includes a number of narrow tubes as the capillary tubes 53. Each capillary tube 53 sprays the liquid to produce the mist. The atomization unit can include a perforated plate that has a number of fine spraying holes instead of capillary tubes. The perforated plate can be formed from an electrically-conductive plate such as a metal plate. The fine spraying holes of the perforated plate can be formed in the metal plate by a laser. The perforated plate can be formed of a sintered metal that has pores as fine spraying holes. The electrically-conductive perforated plate is connected to a high-voltage power supply, and can apply a high voltage between atomization electrodes. The perforated plate is not necessary to have electrical conductivity. The reason is that the liquid has electrical conductivity so that fine liquid droplets are produced from the liquid that is sprayed from the spraying holes by an electrostatic effect when a high voltage is applied between the liquid sprayed and the atomization electrodes. For this reason, an open-cell foam that has fine spraying holes such as plastic foam can be used as the perforated plate.

The atomization electrodes 42 are electrically insulated from the spray device 41 in the spray case 47. A high voltage is applied to the atomization electrode 2 with respect to the spray device 41. For this reason, each atomization electrode 42 and the spray device 41, which are fastened to the spray case 47, are electrically insulated from to each other. In the case in which the spray device of the electrostatic atomizer is fastened to the spray case that is formed of metal and is not electrically insulated from the spray case, the atomization electrodes are electrically insulated from the metal spray case. In the case in which the spray device of the electrostatic atomizer is electrically insulated from the spray case that is formed of metal, the atomization electrodes are fastened to the metal spray case. It is noted that both the spray device and the atomization electrodes, which are fastened to the spray case, can be electrically insulated from the spray case.

An electrical discharge occurs between the atomization electrodes 42 and the electrical discharge protrusions 51 of the spray device 41 so that fine liquid droplets are produced from the liquid that is sprayed from the spray device 41. The atomization electrodes 42 are spaced away from the fine spraying holes 52 on an upstream side in a mist-spraying direction. The atomization electrodes 42 shown in FIG. 5 are annular metal rings 42A, which are arranged under an outer periphery of the nozzle block 54, more specifically, are positioned outside an outer periphery of a group of the capillary tubes 53, which are fastened to the nozzle block 54. The atomization electrodes 42, which are the metal ring shown in FIG. 5, are positioned on paths of the carrier gas that is blown through blowing holes 64 so that the carrier gas blown can reduce attachment of the mist onto the atomization electrodes 42.

The atomization electrode can be formed of a metal net. The atomization electrodes that are formed of a metal net are spaced away from the electrical discharge protrusions 51 in a mist-spraying direction. In the case in which the atomization electrodes are formed of a metal net, a uniform electrical discharge can occur between the atomization electrodes and the electrical discharge protrusions 51 so that fine liquid droplets are produced from the liquid that is sprayed from the fine spraying holes 52.

The atomization electrodes 42 are positioned on the upstream side with respect to their corresponding atomization units 50. In the electrostatic atomizer 40 shown in FIG. 5, the spray device 41 sprays the liquid downward. Correspondingly, the atomization electrodes 42 are arranged under the atomization unit 50.

A high voltage power supply 43 applies a high voltage between the atomization units 50 and the atomization electrodes 42. The high voltage power supply 43 is a DC power supply. Positive and negative sides of the high voltage power supply 43 are connected to the atomization electrodes 42 and the atomization units 50, respectively. Alternatively, positive and negative sides of the high voltage power supply 43 are connected to the atomization units and the atomization electrodes, respectively.

The electrostatic atomizer 40 shown in FIG. 5 has a closed chamber as an air chamber 62, which is located in an upper part of the spray case 47. A partitioning wall 63 is airtightly fastened to the upper part of the spray case 47 to create the air chamber 62. The partitioning wall 63 partitions an interior space of the spray case 47 into the air chamber 62 and a spray chamber 61, and serves as a holder that holds the spray device 41 so that the atomization units 50 are arranged at their predetermined positions. The atomization units 50 of the spray device 41 are fastened to the partitioning wall 63 as the holder, and can spray the liquid into the spray chamber 61. The atomization units 50 are detachably attached to the partitioning wall 63 by coupling bolts 58, which pass through coupling holes 54 e in the flanges 54 a of the nozzle blocks 54, as shown in FIG. 6.

The air chamber 62 is created by a closed structure, and is coupled to the blower 67, which is a gas feeding mechanism, so that the carrier gas that is forcedly blown by the blower 67 passes through the blowing holes 64, which are formed in the partitioning wall 63, into the spray chamber 61. The blowing holes 64 are slit through holes, which are arranged between the atomization units 50. The carrier gas that is forcedly blown can be blown along peripheral parts of the atomization units 50 through the blowing holes 64. The blowing holes are not limited to slit holes. A plurality of circular or polygonal through holes can be formed as the blowing holes between the atomization units so that the carrier gas can be blown toward parts between the atomization units through the blowing holes. The carrier gas that is blown into the spray chamber 61 through the blowing holes 64 carries the mist. The blowing hole 64 is formed between the atomization units 50 adjacent to each other in the spray case 47 shown in FIG. 5. The carrier gas that is blown into the spray chamber 61 through the blowing holes 64 is mixed with the mist that is sprayed from the atomization unit 50 and produced as fine liquid droplets by the atomization electrodes 42. A mixture of the carrier gas and the mist is supplied as the mist-containing air to the static mixer 2.

The atomization units 50 of the spray device 41 are fastened to the partitioning wall 63 on the spray chamber 61 side to spray the liquid into the spray chamber 61 as a shown in FIG. 5. The spray device 41 is coupled to a pump 65, which pressurizes the liquid and supplies the liquid pressurized to the spray device 41. More specifically, the pump 65 pressurizes the liquid 9 that is stored in a liquid tank 66, and supplies the liquid 9 pressurized to the atomization units 50. The pump 65 includes a filter that filters the liquid, and supplies the liquid filtered to the spray device 41. The filter filters out foreign matter that can clog the spray device 41. The pump 65 can apply a high discharge pressure to the liquid to feed a high flow rate of the liquid to be sprayed from the atomization units 50 whereby reducing a mean droplet size of the mist. A mean droplet size of the mist will vary depending not only on a pressure of the liquid that is supplied from the pump 65 but on a structure of the atomization unit 50. For this reason, a pressure of the pump 65, which pressurizes the liquid and supplies the liquid pressurized to the atomization units 50, is specified to an optimum value in consideration of the structure of the atomization units 50 and a required droplet size of the mist. An exemplary suitable pressure of the pump 65 can be preferably not lower than 0.1 MPa, more preferably not lower than 0.2 MPa, most preferably not lower than 0.3 MPa. If a pressure of the liquid that is supplied from the pump 65 to the atomization unit 50 is high, the pump 65 will be expensive, and power consumption by an electric motor that operates the pump 65 will be large so that running costs of the dissolution apparatus will be high. From this viewpoint, a pressure of the liquid that is supplied from the pump 65 to the atomization unit 50 can be not higher than 1 MPa, preferably not higher than 0.8 MPa, more preferably not higher than 0.7 MPa, for example. Most preferably, a pressure of the liquid that is supplied from the pump 65 to the atomization unit 50 is 0.3 to 0.6 MPa.

INDUSTRIAL APPLICABILITY

The dissolution method according to the present disclosure can be used a dissolution method that dissolves into a liquid a water-soluble component (e.g., malodorous component, ammonia, alcohol, volatile organic compounds (VOC), etc.) included in a soluble gas, and collects or remove the water-soluble component. 

1. A dissolution method comprising: oscillating a liquid at an ultrasonic frequency to produce a liquid column; forcedly blowing air to the liquid column produced to separate a mist of the liquid from the liquid column whereby producing mist-containing air; supplying a soluble gas and the mist-containing air to a static mixer; mixing the soluble gas and the mist-containing by using the static mixer; bringing the liquid mist in contact with the soluble gas to dissolve a water-soluble component that is contained in the soluble gas into the liquid mist; and aggregating the liquid mist that contains the water-soluble component dissolved to produce a solution that contains the water-soluble component dissolved.
 2. A dissolution method comprising: spraying a liquid by using a spray device; exposing a sprayed mist of the liquid to an electric field and mixing the mist, and carrier air to produce mist-containing air; supplying a soluble gas and the mist-containing air to a static mixer; mixing the soluble gas and the mist-containing by using the static mixer; bringing the liquid mist in contact with the soluble gas to dissolve a water-soluble component that is contained in the soluble gas into the liquid mist; and aggregating the liquid mist that contains the water-soluble component dissolved to produce a solution that contains the water-soluble component dissolved.
 3. The dissolution method according to claim 1 further comprising adjusting a flow rate of air for producing the mist-containing air to keep the liquid mist in droplets in the static mixer.
 4. The dissolution method according to claim 3 further comprising detecting a temperature or humidity inside the static mixer, wherein the a flow rate of air for producing the mist-containing air is adjusted in the air-flow-rate adjustment in accordance with the temperature or humidity detected.
 5. The dissolution method according to claim 1, wherein the soluble gas contains air, and wherein the method comprises adjusting a flow rate of the soluble gas, which contains air, to the static mixer to keep the liquid mist in droplets in the static mixer.
 6. The dissolution method according to claim 5 comprising detecting a temperature inside the static mixer, and adjusting the flow rate of the soluble gas, which contains air, to be supplied to the static mixer in accordance with the temperature detected.
 7. The dissolution method according to claim 1 comprising adjusting a temperature inside the static mixer to keep the liquid mist in droplets in the static mixer.
 8. The dissolution method according to claim 1 further comprising adjusting an amount of the liquid mist to be supplied to the static mixer to keep the liquid mist in droplets in the static mixer.
 9. The dissolution method according to claim 8 further comprising detecting a temperature inside the static mixer, and wherein the amount of the liquid mist to be supplied to the static mixer is adjusted in the liquid-mist-amount adjustment in accordance with the temperature detected.
 10. The dissolution method according to claim 1 further comprising adjusting a temperature of the soluble gas to be supplied to the static mixer to keep the liquid mist in droplets in the static mixer.
 11. The dissolution method according to claim 10 further comprising supplying air to the soluble gas, and adjusting an amount of the air to be supplied to the soluble gas, wherein the temperature of the soluble gas to be supplied to the static mixer is adjusted in the solution-gas-temperature adjustment by the air-supply-amount adjustment.
 12. The dissolution method according to claim 1, wherein the water-soluble component of the soluble gas is at least one selected from the group consisting of an odorous component, ammonia, alcohol, volatile organic compound (VOC), soot, NOX, and SOX.
 13. The dissolution method according to claim 1, wherein the liquid is water, alkaline water, or acid water.
 14. The dissolution method according to claim 2 further comprising adjusting a flow rate of air for producing the mist-containing air to keep the liquid mist in droplets in the static mixer.
 15. The dissolution method according to claim 14 further comprising detecting a temperature or humidity inside the static mixer, wherein the a flow rate of air for producing the mist-containing air is adjusted in the air-flow-rate adjustment in accordance with the temperature or humidity detected.
 16. The dissolution method according to claim 2, wherein the soluble gas contains air, and wherein the method comprises adjusting a flow rate of the soluble gas, which contains air, to the static mixer to keep the liquid mist in droplets in the static mixer.
 17. The dissolution method according to claim 2 comprising detecting a temperature inside the static mixer, and adjusting the flow rate of the soluble gas, which contains air, to be supplied to the static mixer in accordance with the temperature detected.
 18. The dissolution method according to claim 2 further comprising adjusting a temperature of the soluble gas to be supplied to the static mixer to keep the liquid mist in droplets in the static mixer.
 19. The dissolution method according to claim 18 further comprising supplying air to the soluble gas, and adjusting an amount of the air to be supplied to the soluble gas, wherein the temperature of the soluble gas to be supplied to the static mixer is adjusted in the solution-gas-temperature adjustment by the air-supply-amount adjustment.
 20. The dissolution method according to claim 2, wherein the water-soluble component of the soluble gas is at least one selected from the group consisting of an odorous component, ammonia, alcohol, volatile organic compound (VOC), soot, NOX, and SOX. 